The defining moment of Tomas Alfredson’s interpretation of Tinker Tailor Soldier Spy comes more than halfway through the film. Ricki Tarr (Tom Hardy), an undercover British intelligence agent in the 1970s who’s discovered a critical piece of information about the integrity of the operatives at the service’s upper echelon, recounts for an elder agent the story of how he came by the knowledge that’s now put his life in danger. He talks with George Smiley (Gary Oldman), a senior operative forced into early retirement and now tasked with learning the identity of the highly placed mole who’s leaking data to the KGB wrecking British intelligence from the inside. In the middle of this high-stakes investigation, Ricki’s tale unfolds with the grace and fully formed realization of a short story, as if it exists somehow apart from the larger narrative even as it informs its course. He talks about how he was initially assigned to cover a potentially hazardous Soviet named Boris, only to learn that Boris is a wife-beater and generally worthless human being. Ricki slowly ingratiates himself with Boris’s wife, and what starts as a diverting if businesslike approach to the game becomes complicated when he and the woman develop feelings for one another. Alfredson never rushes the beats of the story, even though they unfold fairly briskly, and he never cheats us out of any emotional moment that would make the flashback work. In addition to the facts of the case, we get the slow blossom of Ricki’s developing relationship, even though it doesn’t seem to have any effect on Smiley’s mole hunt or the bigger story.

This is important for two reasons, and they’re the reasons that make Tinker Tailor Soldier Spy such a fantastic, wonderfully crafted thriller that feels like a relic from another time. One: Alfredson knows how to tell a story with the perfect mix of suspense and relief, of little moments mixed with big ones. Ricki’s love jaunt could realistically be recapped in a quick and dirty exposition dump — tailed a guy, finessed the wife, got the info — but the finely paced and expertly executed vignette is one of many that give the film its style and power. And two: It speaks to the film’s larger goal of living in the tension between slow and fast, between explosion and restraint, and between head and heart. Tinker Tailor Soldier Spy is defined by contrasts, and the juxtaposition of seeming opposites is used to mirror the truth at the core of the film, which is that what often looks like a glamorous or exciting life is usually anything but. In spy stories, the truth is often hard to come by, but Alfredson (drawing from the script by Bridget O’Connor and Peter Straughan, based on John LeCarre’s classic novel) embraces that challenge and demonstrates that if nothing is what it seems, then everything has a dual purpose. The men in his tale are simultaneously caring and aloof, engaged and repressed, powerful and frightened. They know more than anyone else, and they live in the dark.

In another of the film’s many apparent paradoxes, the central story is at once fiendishly complicated and ridiculously simple. When a botched job leads to the ouster of Control (John Hurt) and Smiley from the intelligence service, Smiley takes the reins on a job that Control was just beginning: Ferreting out a mole from the upper ranks of what the agents refer to as “the Circus.” Control’s been tipped off that the mole is one of a handful of senior operatives — Percy Alleline (Toby Jones), Toby Esterhase (David Dencik), Roy Bland (Ciaran Hinds), or Bill Haydon (Colin Firth). Smiley enlists the aid of junior agent Peter Guillam (Benedict Cumberbatch), Ricki’s contact. That’s essentially it, and the writers have done a splendid job trimming to film form what couldn’t have been an easy novel to synthesize. Smiley’s relentless pursuit of the truth forms the spine of the film, and he works diligently and methodically to assemble the puzzle that’s laid out before him. The simplicity and primacy of that hunt allow Alfredson breathing room to veer into character studies, home lives, and broken relationships along the way. He finds the grace notes in the story, and he lets the little moments add color to the field without ever losing focus on the big picture. Side characters come and go, and the rapid-fire clip of Cold War political banter never lets up, but there’s a beauty and focus to the film that keep it from becoming lost in its own potentially complicated story.

Tinker Tailor Soldier Spy is a period piece, too. We’re now four decades removed from the action depicted, a far cry from the handful of years that bridged the gap between the world of the story and the publication of LeCarre’s novel (and subsequent release of the miniseries that starred Alec Guinness as Smiley). As such, Alfredson is able to comment stylistically on the moral ambiguity of the story and the era with hindsight’s accursedly perfect vision. Everything here is brown and gray, muddy and unforgettable; clothes and people are equally impossible to remember or pin down, an echo of the ethical dilemmas that haunt the main characters. (Needless to say, a haze of cigarette smoke covers every office interior.) Alfredson reunites here with cinematographer Hoyte Van Hoytema, with whom he collaborated on Let the Right One In, and they once again bring an austere beauty and formal restraint to the screen with evocative, gorgeous photography. Shots are wider than you’d likely see from an American filmmaker, but it’s not just because Alfredson loves putting his characters in a geographical context you can actually feel. It’s a way of tonally connecting the viewer with the curious spies on screen, forcing us to constantly look or crane to try and get a good look. We become not just viewers, but voyeurs. We’re forever seeing the backs and sides of people’s heads, fleeting glimpses of subjects just slightly out of range. There’s a fantastic sequence reminiscent of Rear Window in which Ricki, spying on Boris in his apartment from a building across the street, is able to see a minor drama play out but remains powerless to stop it. We don’t get a close-up of what’s happening, either. Alfredson grounds us right there in the room.

The entire cast is superb, plain and simple. At the beginning of the film, there’s a sequence with the main characters all seated around a table at their headquarters, and the sheer tonnage of acting firepower assembled is enough to make anyone’s jaw drop a little. Oldman is riveting, especially for a man who barely speaks for much of the film (and who is basically silent for the first quarter hour). He inhabits Smiley as fully as you’d expect, turning him into a slow-moving but keenly insightful spy in the classic sense. Jones nails every note as the bureaucratic asshole Toby, while Firth makes playing a lonely cad look deceptively effortless. Everyone’s performances are doubly effective in that they never give the game away. Smiley’s mole hunt goes down to the wire.

The result is a genuine slow burn of a film, the kind of taut, gripping, realistically paranoid 1970s-flavored psychodrama that hasn’t been turned out on a regular basis since, well, the 1970s. As the central narrative moves faster and faster, Alfredson deftly manages to incorporate character development with story beats, and he also never fails to make the puzzle worth solving. So many filmmakers seem to view mysteries like this one as means to an end, as if the mole hunt were less important than how the characters felt about the whole thing. But Alfredson demonstrates an able hand by not only keeping the mole hunt front and center, but by making sure Smiley’s gradual solving of the puzzle makes sense. Twists and turns are allowed time to resonate; new developments are folded into a cohesive whole. You don’t just watch it; you get it. It’s a study in contradictions that becomes an examination on the endless cause and effect of suspicion and fear. Films like this don’t get made often enough.

Daniel Carlson is the managing editor of Pajiba and a member of the Houston Film Critics Society and the Online Film Critics Society. He’s also a TV blogger for the Houston Press. He tweets more often than he should, and he blogs at Slowly Going Bald.